But the millions spent on research and development might make the sky-high prices of blockbuster drugs understandable. It's a different story for generic drugs. Manufacturers aren’t saddled with R&D expenses or attempting to create a market for new meds, Los Angeles Times explains:

Manufacturers are basically starting with the exorbitant prices that the branded guys charged and then setting their own prices at whatever level they think the market will bear.

Americans spent $758 on average out of pocket for medication in 2012.

So, Consumer Reports’ secret shoppers called over 200 pharmacies throughout the U.S. to get nonmember, nondiscounted prices on a month’s supply of generic versions of five blockbuster drugs: Actos for diabetes, antidepressant Lexapro, Lipitor for high cholesterol, blood thinner Plavix, and Singulair for asthma.

Costco was the least expensive overall.

A few independent pharmacies were even cheaper, but their prices varied widely, as did grocery-store pharmacies.

Online retailers Healthwarehouse.com and FamilyMeds.com also had low prices.

Followed by Sam’s Club, Kmart, Walmart, and Walgreens.

CVS, Rite Aid, and Target had the highest retail prices.

All the drugs combined cost $749 more at CVS than at Costco. Lipitor, for example, was $17 at Costco and $150 at CVS.

"It really comes down to a store's business model,” says Consumer Reports editor Lisa Gill. “For example, big box stores tend to use their pharmacies as a way to get consumers through the door with the expectation that they'll buy other things.”